From: Samuel Holland <samuel@sholland.org>
To: Alessandro Zummo <a.zummo@towertech.it>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Maxime Ripard <mripard@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
Jernej Skrabec <jernej.skrabec@siol.net>
Cc: linux-rtc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org,
Samuel Holland <samuel@sholland.org>
Subject: [PATCH] rtc: sun6i: Add NVMEM provider
Date: Sun, 18 Apr 2021 20:45:49 -0500 [thread overview]
Message-ID: <20210419014549.26900-1-samuel@sholland.org> (raw)
The sun6i RTC provides 32 bytes of general-purpose data registers.
They can be used to save data in the always-on RTC power domain.
The registers are writable via 32-bit MMIO accesses only.
Expose the region as a NVMEM provider so it can be used by userspace and
other drivers.
Signed-off-by: Samuel Holland <samuel@sholland.org>
---
drivers/rtc/rtc-sun6i.c | 42 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
index e75020ab8024..f4a5e7465148 100644
--- a/drivers/rtc/rtc-sun6i.c
+++ b/drivers/rtc/rtc-sun6i.c
@@ -69,6 +69,10 @@
#define SUN6I_LOSC_OUT_GATING 0x0060
#define SUN6I_LOSC_OUT_GATING_EN_OFFSET 0
+/* General-purpose data */
+#define SUN6I_GP_DATA 0x0100
+#define SUN6I_GP_DATA_SIZE 0x20
+
/*
* Get date values
*/
@@ -641,6 +645,39 @@ static const struct rtc_class_ops sun6i_rtc_ops = {
.alarm_irq_enable = sun6i_rtc_alarm_irq_enable
};
+static int sun6i_rtc_nvmem_read(void *priv, unsigned int offset, void *_val, size_t bytes)
+{
+ struct sun6i_rtc_dev *chip = priv;
+ u32 *val = _val;
+ int i;
+
+ for (i = 0; i < bytes / 4; ++i)
+ val[i] = readl(chip->base + SUN6I_GP_DATA + offset + 4 * i);
+
+ return 0;
+}
+
+static int sun6i_rtc_nvmem_write(void *priv, unsigned int offset, void *_val, size_t bytes)
+{
+ struct sun6i_rtc_dev *chip = priv;
+ u32 *val = _val;
+ int i;
+
+ for (i = 0; i < bytes / 4; ++i)
+ writel(val[i], chip->base + SUN6I_GP_DATA + offset + 4 * i);
+
+ return 0;
+}
+
+static struct nvmem_config sun6i_rtc_nvmem_cfg = {
+ .type = NVMEM_TYPE_BATTERY_BACKED,
+ .reg_read = sun6i_rtc_nvmem_read,
+ .reg_write = sun6i_rtc_nvmem_write,
+ .size = SUN6I_GP_DATA_SIZE,
+ .word_size = 4,
+ .stride = 4,
+};
+
/* Enable IRQ wake on suspend, to wake up from RTC. */
static int sun6i_rtc_suspend(struct device *dev)
{
@@ -728,6 +765,11 @@ static int sun6i_rtc_probe(struct platform_device *pdev)
if (ret)
return ret;
+ sun6i_rtc_nvmem_cfg.priv = chip;
+ ret = devm_rtc_nvmem_register(chip->rtc, &sun6i_rtc_nvmem_cfg);
+ if (ret)
+ return ret;
+
dev_info(&pdev->dev, "RTC enabled\n");
return 0;
--
2.26.3
next reply other threads:[~2021-04-19 1:45 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-19 1:45 Samuel Holland [this message]
2021-04-30 9:02 ` [PATCH] rtc: sun6i: Add NVMEM provider Maxime Ripard
2021-05-04 15:33 ` Alexandre Belloni
2021-05-10 3:39 ` Samuel Holland
2021-05-10 8:00 ` Alexandre Belloni
2021-05-25 8:24 ` Maxime Ripard
2021-05-27 4:09 ` Samuel Holland
2022-04-13 23:17 Samuel Holland
2022-04-15 18:26 ` Jernej Škrabec
2022-05-17 20:49 ` alexandre.belloni
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